You throw a ball straight up from a rooftop 30 feet high with an initial speed of 48 feet per second. The function s(t)= 16t^2 + 48t + 30 models the ball’s height above the ground, s(t), in feet, t seconds after it was thrown.

During which time period will the halls height exceed the rooftop?

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

step-by-step explanation:

left be aligning the decimal points is required to not required see the number of digits to the right